Explanation:
What is that light in the sky?
Perhaps one of humanity's more common questions,
an answer may result from a few quick observations.
For example -- is it moving or blinking?
If so, and if you live near a city,
the answer is typically an airplane,
since planes are so numerous and so few stars and
satellites are bright enough to be seen over the din of
artificial city lights.
If not, and if you live far from a city, that bright light is likely a planet such as
Venus or
Mars --
the former of which is constrained to appear near the horizon just before dawn or after dusk.
Sometimes the low apparent motion of a distant
airplane near the horizon makes it hard to tell from a
bright planet,
but even this can usually be discerned by the plane's motion over a few minutes.
Still unsure?
The above chart gives a sometimes-humorous but mostly-accurate assessment.
Dedicated sky enthusiasts will likely note -- and are
encouraged to provide --
polite corrections.